POSSIBLE SIDE EFFECTS OF RADIATION ONCOLOGY

Radiotherapy is a modern, targeted and effective treatment. This means there can be predicted or unpredicted side-effects that, in most cases, are mild. More serious complications and medical errors are possible like elsewhere in medicine. Radiation-oncology departments have however a strong tradition in strict quality control measures, that strongly increase safety.

For patients and family members without training in medicine or physics, the technical functioning of radiotherapy systems seems very complex, and this might be frightening. This website can help you to better understand radiotherapy, and we hope your radiation oncologist will be able to offer additional information concerning your disease and the treatment.

Most radiotherapy treatments are done in several steps: a consultation, a simulation, and then a series of treatments. A patient may still have some anxiety in the beginning because of fear of the unknown, but as the treatment progresses many patients realize that they are well surrounded by the medical team and that the treatment is easier than they would have thought.

Don't forget: radiotherapy does not 'burn' and does not make people radioactive.

Below you will find:

Information on the measures taken by the medical team to make the treatment as effective as possible

Information on what patients can do to make the treatment as successful as possible

Information on short-term versus long-term side effects

Some short-term side effects

Some long-term side effects

Specific information on skin care

Prevention of side effects of the medical team

High precision treatments

The best preventive measure of side effects is to concentrate the radiotherapy dose as much as possible on the tumour, and to reduce as much as possible the dose on the surrounding healthy organs that do not need to be irradiated. This seems logical, but in the past, it was not always technically possible. The biggest progress in radiation oncology in the last years was the development of a large array of tools to make treatments ever more precise. See the glossary for an explanation on IMRT, IGRT, rotational therapy and other terms. Don't hesitate to ask the radiation oncologist which measures have been taken for the treatment.

Record and verify systems

Radiation-oncologists and physicists introduced automated systems over 25 years ago to continuously register the correct application of the treatment. This means that a computer system sends treatment-related data to the treatment machine, without the risk that humans might send wrong data. In addition, during the treatment, all steps taken by the technologists and by the machine itself are automatically recorded. This allows verifying at a later stage exactly what has been done. This is quite unique in the medical world!

In vivo dosimetry

At a specific point where the treatment beam enters or leaves the body, a detector can be applied to the skin of the patient to measure exactly what dose of irradiation did pass here. The obtained measurement during a real treatment is then compared to what the theoretical dose should have been as calculated by the treatment planning computer. In case of a deviation of what was expected, the source of the deviation is investigated. This can help to prevent imprecisions in the calculation, but also mistakes in placing the patient correctly on the table for instance. Some in-vivo dosimetry systems do not need detectors applied on the skin at the entrance or the exit of the treatment beam, because they use other detectors at a larger distance from the patient.

Quality control procedures

The in-vivo dosimetry explained above is just one of the possible quality control procedures. The medical, physics and technologists’ team have a whole array of supplementary quality control systems to check the correct execution of the treatment. Most of these systems are based on extra images being obtained before/during/after the treatment to check the correct positioning of the tumour relative to the treatment beams.

College of radiotherapy

Radiation oncologists share their quality control data and experiences in a dedicated quality control group, referred to as the 'college of radiotherapy'.

Prevention of side effects by the patient

Get informed

Your radiation oncology team will probably give you a lot of good advice concerning the treatment. You might get leaflets or brochures relevant to your specific treatment. If you did not get any specific information, please contact your radiation oncology team. Topics you might want to be informed on are:

Skincare during radiotherapy

Nutrition during radiotherapy

Taking care of your mouth during radiotherapy

Transport problems during radiotherapy

Immobilisation material used during radiotherapy

...

Follow guidelines

Getting informed is not enough... patients also have to respect the guidelines they receive. If you are unable to do this, it is best to honestly discuss this with the radiation oncology team. They might have extra help at hand where needed.

Communicate with your radiation team

All problems and side effects (expected or not) should be communicated to the radiation oncology team. You may get polls, questionnaires and documents to fill in, but there is no harm indirectly contacting the technologist staff at the treatment machine or to ask to see the radiation oncologist in person if you want further information or explanations.

Stop smoking

Of all the great tips you could get as a patient, this is a very important one:try and stop smoking. Smoking does increase the risk of new cancers, smoking makes you weaker, smoking can sometimes reduce the effectiveness of radiation because there is less oxygen in your tissues, and smoking can increase some side effects of radiation. Get help, and stop smoking!

Effects of radiotherapy are usually local

Contrary to systemic treatment, radiotherapy is a local treatment. This means that both the beneficial and the undesired effects of radiation are only seen in the area that actually gets irradiated. So, if a patient gets pain in the left leg during radiotherapy of the right arm, it is very unlikely there is a relation between the treatment and the problem. There are some exceptions, like fatigue, and some rare neurological conditions.

Information on short-term versus long-term side effects

Early side effects: Some side effects appear immediately after the radiotherapy – within hours, days or a few weeks

Late side effects: Other side effects only get noticed after many weeks to months after a treatment.

For some (but not all) side effects, there is a possible correlation between the two: having few side effects shortly after the treatment often predicts that it is likely that there will be little long-term side effects.

The relation between short- and long-term side effects, between dose and side effects, and between the irradiated volume of the human body and side effects, is complex. Therefore, each individual patient will personally be informed by the radiation oncologist on what is a likely pattern of side effects after a given treatment.

Short-term side effects are usually very temporary, but in most cases, long-term side effects will disappear over time as well.

Patients and their family members can find a list of some side effects below.

Some short-term side effects

Fatigue (possible after most radiotherapy treatments)

Loss of appetite, nausea (only if the abdomen or the brain is irradiated)

Diarrhoea (only if the abdomen is irradiated)

Skin irritation (see below)

Bladder irritation (only if the lower abdomen is irradiated)

Etc.

Some long-term side effects

The rigidity of joints or muscles (only if these were irradiated)

Skin colour changes (only if the skin dose was relatively high)

Reduction of the respiratory capacity (only if the lung was irradiated)

...

Specific information on skin care

This is a specific side effect for which we reserve a special paragraph.

During external beam radiotherapy, the irradiation beams always have to cross the skin first before arriving on the target volume on the inside of the body. Because the skin is a rapidly growing organ, skin can suffer from the irradiation. On the other hand, the energy of the treatment beams used makes sure that the irradiation dose is higher deeper in the human body, and lower close to the skin. Anyhow, skin side effects were well known after radiation in the past. That is why some people might tell that 'irradiation burns your skin'. With modern radiotherapy, this is hardly the case. In some specific situation, where the tumour is not far from the skin and a high irradiation dose is needed, there can still be skin problems during and after the treatment.

Skin problems can require preventive measures, and in case the skin irritation starts, a series of treatments are also available. Please do NOT start using any medication, cream, ointment, milk, clay, lotion or whatever on the irradiated skin before first discussing this with the radiation team. They are often best informed about what is the best approach. There is generally NO need to see a dermatologist. Nowadays, skin problems are more often treated with a special wound dressing, rather than with lotions or creams. Talk to the radiation oncologist!